Vitiligo impact scale: an instrument to assess the psychosocial burden of vitiligo.

BACKGROUND Vitiligo is a disease that significantly impairs quality of life. Previous studies have shown that vitiligo has an impact that may not correlate with the size and extent of depigmentation, indicating a need for an independent measure of the psychosocial burden. AIMS To develop a rating scale to assess the psychosocial impact of vitiligo. METHODS The study was undertaken in three broad phases: item generation, pre- and pilot testing, and test administration. Items were generated largely from a qualitative study using semi-structured interviews of patients. Face and content validity were assessed through pre- and pilot testing in 80 patients and the final version was administered to 100 patients who also received the Dermatology Life Quality Index (DLQI) and the Skindex-16. Each patient also underwent a physician global assessment (PGA) of the impact of vitiligo. Test-retest reliability was assessed in 20 patients. RESULTS Of 72 items initially generated for the scale, 27 were retained in the final version. Subjects were able to comprehend the items and took about 5-7 min to complete the instrument. The scale was internally consistent (Cronbach's α = 0.85). Scores on the scale correlated moderately well with the DLQI and the Skindex (Spearman rank correlation: 0.51 and 0.65, respectively). The scale was able to discriminate between patients having mild and those having moderate and severe impact as assessed by PGA. The test-retest reliability coefficient (Spearman rank correlation) was 0.80. CONCLUSION The Vitiligo Impact Scale appears to be a valid measure of the psychosocial impact of vitiligo and this instrument may be useful both in the clinic and in clinical trials.